The Snowmen had an overnight audience of 7.59 million viewers, a share of 33.9% of the total TV audience.
Doctor Who was the fifth most-watched programme of the day, which saw BBC One take seven of the top ten places in the ratings chart. The most watched programme of the day was EastEnders which had 9.4 million watching.
ITV1's highest rated show of the day was Coronation Street with 8.6 million viewers.
Doctor Who was down on last year's overnight figure, which saw the show transmitted in a much later time slot, where it had 8.9 million watching. This year, against the Doctor, Emmerdale achieved 4.7 million viewers.
Despite its early start, Doctor Who out-rated some prime time shows including the Christmas episode of Downton Abbey and Call The Midwife.
Final figures, which will include those who record the programme and watch it later, will be available next week.